1. Field of the Invention
The invention relates to a coupling device, more particularly to a coupling device that is adapted to be used with a standard non-power providing directional tap for drawing and mixing alternating current (AC) power and radio frequency (RF) signals therefrom.
2. Description of the Related Art
FIG. 1 illustrates how cable television signals are supplied to customers or subscribers 3 in a conventional manner. As shown, coaxial signal cables 1 are tapped by means of directional taps 2. The customers 3 are connected to these signal cables 1 via the directional taps 2. The signal cables 1 carry both AC power and RF signals. The AC power signal is used to drive RF signal amplifiers (not shown) distributed along the path from the cable television provider to the customers 3. The RF signal contains cable television signals. Currently, most of the known directional taps 2, such as those manufactured by Signal Vision Inc., Scientific Atlanta, General Instruments, Phillips and Regal, supply only the RF signal to the households 3.
Referring to FIG. 2, each directional tap 2 has a rear housing side that is provided with a clamping unit 25. The clamping unit 25 permits mounting of the directional tap 2 on an aerial support cable 5 that is parallel to the signal cables 1. The clamping unit 25 also permits mounting of the directional tap 2 to ground rods or in other applications, such as underground vaults, pedestals or security boxes.
In this multimedia age, network interface devices are being developed to enable customers to receive and send a variety of RF signals, such as television and telephone signals, along a single cable. Such network interface devices may require both AC power and RF signals as inputs. Thus, the conventional directional taps 2 are not adapted for use with the network interface devices.
In order to use the network interface devices, the conventional directional taps 2 should be replaced to permit the supply of both AC power and RF signals to each customers 3. However, this solution is not cost efficient in view of the need to discard all of the conventional directional taps 2.